QT在Widget上绘制图片

Question

刚学QT，就是重写一个widget类，在这个里面操作，但这个显示图片不知道哪里不对，望指点

MainWindow.h

#pragma once

#include <QtWidgets/QWidget>
#include "ui_MainWindow.h"
#include "MyWidget.h"

class MainWindow : public QWidget
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = Q_NULLPTR);
protected slots:
    void openFile();
private:
    Ui::MainWindowClass ui;
    MyWidget* mywidget;
};

MainWindow.cpp

#include "MainWindow.h"
#include <qpainter.h>
#include <qfiledialog.h>

MainWindow::MainWindow(QWidget *parent)
    : QWidget(parent)
{
    ui.setupUi(this);
    mywidget = new MyWidget();
    connect(ui.openFile, SIGNAL(clicked()), this, SLOT(openFile()));
}
void MainWindow::openFile()
{
    QString curPath = QDir::currentPath();//获取系统当前目录
    QString dlgTitle = "选择一张图片"; //对话框标题
    QString filter = "图片文件(*.jpg *.png)"; //文件过滤器
    QString aFileName = QFileDialog::getOpenFileName(this, dlgTitle, curPath, filter);
    if (!aFileName.isEmpty())
        mywidget->setImage(aFileName);
}

MyWidget.h

#pragma once
#include <qwidget.h>
#include <qpainter.h>
#include <qimage.h>
#include <qtimer.h>
class MyWidget :
    public QWidget
{
public:
    MyWidget(QWidget* parent = 0);
    void setImage(QString name);
protected:
    void paintEvent(QPaintEvent*);
    
private:
    QPainter* painter;
    QImage image;
};

MyWidget.cpp

#include "MyWidget.h"

MyWidget::MyWidget(QWidget* parent):QWidget(parent)
{
	painter = new QPainter;
}

void MyWidget::paintEvent(QPaintEvent*)
{
	painter->begin(this);
	painter->drawImage(QRectF(0, 0, width(), height()),image);
	painter->end();
}

void MyWidget::setImage(QString name)
{
	QImage img;
	img.load(name);
	if(!img.isNull())
        image = img;
}

Answer 1

MyWidget类修改如下，如有帮助，忘采纳，谢谢。

Mywidget.h如下：

class MyWidget : public QWidget
{
public:
    MyWidget(QWidget* parent = 0);
    void setImage(QString name);
protected:
    void paintEvent(QPaintEvent*);
    
private:
    QImage image;
};

Mywidget.cpp如下

#include "MyWidget.h"
#include <QPainter>
MyWidget::MyWidget(QWidget* parent):QWidget(parent)
{
}
 
void MyWidget::paintEvent(QPaintEvent*)
{
    QPainter painter(this);
    painter.drawImage(QRectF(0, 0, width(), height()),image);
}
 
void MyWidget::setImage(QString name)
{
    if(!name.isEmpty())
    {
        image.load(name);
        update(); //调用paintEvent重绘，缺了这句话不会重绘的
    } 
}